Chapter 1 - Whole Numbers - 1.2 Adding Whole Numbers - 1.2 Exercises - Page 18: 5

$317+572=889$

First, add the digits in the ones column (each number's ones place) to determine the digit in the ones place of the sum: $7+2=9$ Next, add the digits in the tens column (each number's tens place) to determine the digit in the tens place of the sum: $1+7=8$ Then add the digits in the hundreds column (each number's hundreds place) to determine the digit in the hundreds place of the sum: $3+5=8$ If the sum has $8$ in the hundreds place, $8$ in the tens place and $9$ in the ones place, it must be $889$.